1. Field of the Invention
The invention concerns a device for supporting and driving a rotatable part of a gantry of a computed tomography apparatus—which gantry has a system axis—relative to a stationary of the gantry of the computed tomography apparatus. The invention also concerns a computed tomography apparatus that embodies such a device.
2. Description of the Prior Art
Computed tomography apparatuses of the third generation have a gantry with a stationary part and a part that can be rotated relative to the stationary part. The rotatable part has the shape of a drum on which are arranged the components of the computed tomography apparatus (such as the x-ray source, the x-ray detector, a control system, etc.), which components revolve around a patient arranged along the system axis in a measurement field during operation of the computed tomography apparatus. In a system with only one x-ray source and one x-ray detector, a completely populated drum has a mass of approximately 800 kg to 900 kg and rotates with a rotation speed of up to 240 R/min during operation.
Roller bearings in different forms are presently used to support the drum relative to the stationary part of the gantry. However, the roller bearings are subject to a certain wear and must be regularly serviced (re-oiled, for example).
For example, the drive may be a motor interacting with a worm gear. Moreover, the noise level emanating from the roller bearings increases with increasing rotation speed such that it can be perceived as disruptive, and additional measures can be necessary to reduce it. The driving of the drum normally takes place via a drive belt.